From feedback I've received from both Yelp CMs and some busted businesses, Yelp will flag a business without warning. It is not necessary to specifically state that you reward good reviews - compensating anyone for any reviews is enough to get flagged. Providing compensation of any kind for changing a review will trigger a flag as well.

How to people get busted? It is often competitors receiving the offer and forwarding it to Yelp via the support page. Active Yelpers who receive compensation offers usually forward review solicitation messages to Yelp Community Managers. Its active Yelpers who flag a lot of the mass email offers like those from RevLeap.com.

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Yelp seems to keep these notices up around 90 days - businesses get a slap-on-the-wrist letter as well. They also seem to apply a manual filter to the suspicious reviews; reviewers that may have participated in compensated reviews apparently get nasty notes as well.

None of the companies that had their warnings removed are Yelp advertisers. I have been informed by insiders at Yelp that while the violation notice is in place, the companies cannot advertise and no one can solicit them for an advertising contract.

Yelp seems to keep these notices up around 90 days - businesses get a slap-on-the-wrist letter as well. They also seem to apply a manual filter to the suspicious reviews; reviewers that may have participated in compensated reviews apparently get nasty notes as well.

None of the companies that had their warnings removed are Yelp advertisers. I have been informed by insiders at Yelp that while the violation notice is in place, the companies cannot advertise and no one can solicit them for an advertising contract.